DHL Supply chain now has a total of 101 LNG and diesel dual-fuel tractor units in the UK, with another 51 already on order - making this the largest dual-fuel HGV fleet in the country.

Source: TransportEngineer.org.uk

Author: Brian Tinham

The announcement follows DHL's latest conversion of a fleet of 63 new Volvo trucks at its flagship consumer and life sciences distribution hub, in Bawtry, Yorkshire, which went live early in September this year. The company expects to expand this fleet to 70 or 80 to cope with the peak trading period of Christmas.

The rest of DHL Supply Chain's existing dual-fuel fleet – all also FH 460s – comprises 27 in Scunthorpe, two operating out of Crick (Dirft) and three on temperature-control duty from Wisbech. DHL is also running a further six Volvo dual-fuel tractor units into continental Europe.

Ian MacAulay, innovation and business development manager with DHL Supply Chain, explains that conversion of its latest Volvo tractor units – each of which will be hauling semi-trailers in the 40—44 tonne range, double shifted and averaging 180,000km per year – is part of DHL Supply Chain's GoGreen agenda, which aims to reduce carbon emissions company-wide by 30% against 2007's figures, by 2020.

"Diesel is a huge area of focus for DHL globally, but the UK has our largest diesel commercial vehicle fleet – 7,500 vehicles and 10,000 trailers – which contributes 87% of our carbon footprint," states MacAulay.

"So this is a big focus for us... Diesel also represents about 75% of the whole life costs of our trucks," he continues. "The expectation is 10—14% carbon saving running on fossil energy. So that's an annual saving of 1,200 tonnes of CO2 across the 63 units at Bawtry, which is equivalent to 5,933 semi-trailers full."

As for the mix of Volvo factory-fit systems and CAP aftermarket conversions, he says: "We need to understand both technologies, in terms of longevity and cost. So we're putting them in the business for a substantial period of time to get the right balance."

Christina Eriksson, Volvo's business manager for alternative drivelines, states that the main differences concern the number of gas injectors and the detail of the integration.

"We doubled the number of gas injectors from six in the CAP retrofit unit, to 12 in our factory-fit version to improve the precision of gas injection control," she says.

"That allows an increase in the substitution rate and higher percentage of methane – so a more efficient solution. But we've also fully integrated the system fully into our product so that it communicates two-way with the ECU, rather than being read-only off the Volvo CANbus."

Also crucial to the Bawtry project, which cost DHL around £8.1 million, is a state-of-the-art, zero-losses LNG refuelling station, developed, installed and operated by BOC. MacAulay estimates payback on the total investment well within three years.

"We've done a lot of other interventions already, including speed reduction, specifying fully-automated transmissions across the fleet and aerodynamic initiatives, but it's clear that in heavy transport there are very few other viable options," states MacAulay.

"So we believe dual-fuel is the way to go where the duty cycle and environment fits – which, for us, sits around 40—44 tonne high mileage trunking with tractor and semi-trailer combinations. That's the best saving."